Technical Field
This disclosure relates to a recording medium conveyor and an image forming apparatus incorporating the recording medium conveyor.
Related Art
An image forming apparatus typically include a recording medium conveyor by which a recording medium is discharged to a sheet discharging device after an image is fixed to the recording medium by a fixing device. Such a sheet discharging device generally includes a driving roller and a driven roller.
Sheet discharging devices are expected to provide higher performance solution for preventing curling of a recording medium and for stacking the recording medium. In order to meet market demand, a known sheet discharging device includes a stiffening roller to stiffen a recording medium. The stiffening roller has an elastic body disposed on the same side as at least one driven roller. The stiffening roller can be disposed on the same side as at least one driving roller, as well. With these configurations, a recording medium is stiffened.
The above-described configuration, however, stiffens a recording medium with a stiffening roller having a large diameter. The large diameter stiffening roller extends and projects toward a nip region formed by a discharging roller. In such a case, the stiffening roller has a diameter greater than the sheet discharging roller. Therefore, regardless of whether the stiffening roller is disposed on the same side as the driving roller or the driven roller, a peripheral speed of the stiffening roller is greater than a peripheral speed of the sheet discharging roller.
With this configuration, the stiffening roller rubs the recording medium, defect such as gloss streaks is generated on an image formed on the recording medium. Consequently, removal of curl of a recording medium by stiffening the recording medium and higher stackability of the recording medium are not incompatible with prevention of image defect.